Profiling developmental speech sound  disorders: differences, deficits and  outcomes

There is evidence that many pre-schoolers with speech sound disorders (SSD) will resolve their SSD without therapy. The identification of children who are likely to resolve without help would avoid resources being expended on children who do not need therapy. Conversely, identification of sub-groups with specific underlying deficits that lead to persisting SSD would allow intervention to target the source of the difficulty. 

Research questions:

Are profiles of SSD associated with other cognitive difficulties? 

Do sub-types of children classified by symptomatology remain stable? 

Which children’s SSD do not resolve? 

Eighty-five children referred to local SLT services with suspected SSD were assessed on a battery of tests for speech, language and other cognitive abilities. Seventy-five children were reassessed two years later to establish changes in diagnostic profile and outcomes.

At time 1 exploratory factor analysis identified clearly defined factors (of which one was speech accuracy), suggesting speech accuracy in pre-schoolers is largely independent of language, motor or cognitive-linguistic abilities. Sub-groups of children with SSD defined by symptomatology or proposed aetiology were not differentiated by profiles of underlying deficits. Symptomatology changed as children aged, suggesting a continuum of delay mediated by age and severity rather than qualitatively different disorders.

Longitudinal follow up showed that 79% of children normalised their speech after 2 years, with or without therapy. Logistic regression indicated that the most clinically useful predictor of recovery was the child’s score on a test of Non-Word Discrimination. Lateralised fricatives did not resolve.

Clinical implications are discussed.